The present invention relates generally to jacks for use in electrical connectors and, more particularly, to jacks for modular plugs adapted for connection to printed circuit boards.
The termination of multi-conductor cord by modular plugs has become commonplace. Examples of such modular plugs are disclosed in various patents, such as U.S. Pat. Nos. 3,699,498, 3,761,869, 3,860,316 and 3,954,320. Another advantageous configuration of a modular plug is disclosed in U.S. Pat. No. 4,211,662 assigned to Stewart Stamping Corporation, assignee of the instant application. Essentially, the modular plug includes a dielectric housing having a cavity into which an end portion of the cord is received. Flat contact terminals corresponding in number to the number of cord conductors are inserted into respective slots which open at one housing side and which are aligned with the conductors so that blade-like portions of the contact terminals pierce respective cord conductors. Straight upper edges of the contact terminals are exposed at the side of the housing in position for engagement by respective jack contacts when the modular plug is inserted into the jack.
It is becoming more commonplace to connect the conductors of multi-conductor cords to the conductors of printed circuit boards, such as in computers, through the use of modular plugs. Accordingly, jacks for modular plugs have been designed specifically for connection to printed circuit boards.
However, the applicability of modular plug-jack connectors to printed circuit board connections, such as in computers, has in the past been limited by the geometry of the electronic equipment and conventional plugs and jacks. Computers often include components consisting of a plurality of printed circuit boards stacked one over the other in closely spaced overlying relationship. For example, a computer may have printed circuit boards stacked one over the other with adjacent boards being spaced only slightly more than one-half inch from each other. Since the height of conventional modular plugs is already about 3/8 inch, their use in environments of the type described above, keeping in mind the necessity of providing a jack for receiving the plug, is clearly limited.
Jacks for modular plugs have been designed which enable the use of the modular plugs in the limited available spaces of the type described above. Such jacks are designed with low profiles, i.e., with height dimensions of about one-half inch. Conventional jacks of this type, such as those available from Virginia Plastics Company of Roanoke, Va., generally comprise a one-piece plastic housing having a longitudinal cavity adapted to receive the modular plug. Associated with the housing are a plurality of jack contacts adapted to engage the straight edges of the contact terminals of the plug when the latter is inserted into the jack receptacle. Each jack contact is held by slots or grooves formed in the jack housing and includes a portion which extends along the outside of the rear housing wall and projects below the bottom of the jack housing for insertion into the printed circuit board and a portion which extends along the outside of the top wall through a slot formed therethrough into the jack receptacle for engagement with the edge of a respective contact terminal of the plug.
Jacks of this type are not entirely satisfactory for several reasons. For example, the jack contacts are exposed externally of the jack both at the rear as well as at the top wall thereof thus subjecting the contacts to possible damage during use. Portions of the jack contacts tend to be pushed out or become loosened from the slots or grooves which hold them in place. Furthermore, the jack contacts do not provide sufficient contact pressure against the plug contacts when the plug is inserted into the jack to ensure a reliable electrical connection.
Jacks for modular plugs adapted for connection to printed circuit boards are disclosed in U.S. Pat. No. 4,537,459 and co-pending applications Ser. Nos. 612,722, 655,696, and 806,679 assigned to the assignee of the instant application All of these jacks provide means for EMI/RFI shielding. However, not all of these jacks satisfy the height requirements for use in applications of the types described above and the construction of such jacks is somewhat complicated.